A lithium-ion battery

Abstract

The utility model belongs to battery technical field discloses a kind of lithium ion batteries, including pole group, side plate, end plate, shell and cover plate, pole group is provided with bending part;Side plate and end plate are enclosed to form the accommodation space for accommodating pole group, the position of bending part is provided with support portion in side plate inner wall;Pole group, side plate and end plate are all arranged in shell interior;Cover plate is connected with shell, cover plate is provided with explosion vent, end plate is arranged in the end of side plate towards explosion vent, end plate is provided with opening portion in the position corresponding explosion vent, opening portion is communicated with accommodation space.Such, side plate and end plate can provide stable support to pole group, support portion can improve the structural strength of bending part, avoid forming weak area, end plate can separate pole group end and explosion vent, so that explosion vent can keep normal exhaust, improve the security and stability of lithium ion battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries are widely used in consumer electronics, new energy vehicles, energy storage and other fields. Common electrode assembly methods include winding and stacking. Among them, wound lithium-ion batteries have advantages such as relatively simple process, low manufacturing cost and high assembly efficiency, and are more widely used.

[0003] However, wound battery cells have relatively low volumetric energy density, and the wound electrodes have many bending areas, resulting in significant stress within the electrode material. At the end of the battery cell's life cycle and in the event of thermal runaway, these bending areas may evolve into weak points in the electrode assembly, affecting the cell's electrical and safety performance. Furthermore, when a battery cell experiences thermal runaway, a large amount of gas and heat is generated internally, causing the electrodes to be impacted. The bending areas of the electrodes are prone to breakage under the impact of gas, which can then be ejected from the explosion-proof valve. The high-temperature electrodes often carry sparks, which can easily ignite flammable materials outside the battery cell, leading to a fire and explosion. The large amount of gas generated inside the battery cell can also cause the electrode assembly to shift and block the explosion-proof valve, resulting in pressure buildup inside the battery cell and potentially causing an explosion. Therefore, wound batteries have relatively poor safety and stability. Utility Model Content

[0004] The purpose of this invention is to provide a lithium-ion battery to solve the problem of poor safety and stability of batteries wound into groups.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A lithium-ion battery includes: an electrode assembly having a bent portion; a side plate and an end plate forming an accommodating space for housing the electrode assembly, wherein a support portion is provided on the inner wall of the side plate corresponding to the bent portion; a housing having the electrode assembly, side plate, and end plate disposed inside the housing; and a cover plate connected to the housing, having an explosion-proof valve disposed on the cover plate, wherein an end plate is disposed at the end of the side plate facing the explosion-proof valve, and an opening is provided on the end plate corresponding to the explosion-proof valve, the opening communicating with the accommodating space.

[0007] Preferably, the surface curvature of the support portion facing the bending portion is equal to the curvature of the bending portion.

[0008] Preferably, the opening extends along the height direction of the electrode group, and the cross-sectional area of ​​the opening is smaller than the cross-sectional area of ​​the end of the electrode group.

[0009] Preferably, a first through hole is provided on the side plate and a second through hole is provided on the end plate, both of which are connected to the accommodating space.

[0010] Preferably, the diameter of the first through hole is in the range of 2mm-5mm; and / or, the diameter of the second through hole is in the range of 2mm-5mm.

[0011] Preferably, multiple first through holes are provided, and the multiple first through holes are provided on both sides of the opening along its length.

[0012] Preferably, the thickness of the outer shell is in the range of 0.3mm-1mm.

[0013] Preferably, the side plate has a length of L1 and the outer shell has a length of L2, and L2-L1≥5mm.

[0014] Preferably, the length of the end plate is L3, the minimum length of the opening is L4, and L3-L4≤20mm is satisfied.

[0015] Preferably, the gap between the bent portion and the supporting portion is less than 1 mm.

[0016] The beneficial effects of this utility model are:

[0017] A lithium-ion battery includes an electrode assembly, a side plate, an end plate, a housing, and a cover plate. The electrode assembly has a bent portion. The side plate and the end plate enclose a housing space for accommodating the electrode assembly. A support portion is provided on the inner wall of the side plate corresponding to the bent portion. The electrode assembly, side plate, and end plate are all disposed inside the housing. The cover plate is connected to the housing and has an explosion-proof valve. The end plate is disposed at the end of the side plate facing the explosion-proof valve, and an opening is provided on the end plate corresponding to the explosion-proof valve, the opening communicating with the housing space.

[0018] In this way, the side plates and end plates can stably support the electrode assembly and limit its position, preventing the electrode assembly from shifting under the impact of a large amount of gas generated by thermal runaway. The support part can improve the structural strength of the bending part, preventing the formation of weak areas and cracking and breakage. The end plates can separate the electrode assembly end and the explosion-proof valve, preventing the electrode assembly end from shifting and blocking the explosion-proof valve. This allows the gas generated inside the lithium-ion battery to be discharged to the outside through the opening and the explosion-proof valve, achieving timely pressure relief, reducing the risk of explosion and fire, and improving the safety and stability of the lithium-ion battery. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a lithium-ion battery in one embodiment of the present invention;

[0020] Figure 2This is a side view of a lithium-ion battery according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the side plate and end plate in one embodiment of the present invention.

[0022] In the picture:

[0023] 1. Pole assembly; 2. Side plate; 21. First through hole; 3. End plate; 31. Opening; 32. Second through hole; 4. Accommodation space; 5. Outer shell. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0025] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0028] See Figures 1 to 3 This utility model provides a lithium-ion battery, including an electrode assembly 1, a side plate 2, an end plate 3, a housing 5, and a cover plate (not shown in the figure). The electrode assembly 1 is provided with a bent portion (not shown in the figure). The side plate 2 and the end plate 3 enclose and form a housing space 4 for accommodating the electrode assembly 1. A support portion (not shown in the figure) is provided on the inner wall of the side plate 2 at the position corresponding to the bent portion. The electrode assembly 1, the side plate 2, and the end plate 3 are all disposed inside the housing 5. The cover plate is connected to the housing 5 and is provided with an explosion-proof valve. The end plate 3 is disposed at the end of the side plate 2 facing the explosion-proof valve. The end plate 3 is provided with an opening 31 at the position corresponding to the explosion-proof valve, and the opening 31 communicates with the housing space 4.

[0029] In this embodiment, the electrode assembly 1 is a square structure with a wound design. The lithium-ion battery also includes an insulating film (not shown in the figure). The insulating film covers the electrode assembly 1. There are two bending parts, which are respectively located on both sides of the electrode assembly 1 in the height direction. The support parts are respectively located on the inner walls of the two side plates 2 in the height direction of the electrode assembly 1. The side plates 2 and the end plates 3 are both made of mica material and are integrally formed. The side plate 2 is open at the end away from the end plate 3 to facilitate the insertion of the electrode assembly 1 into the shell. The end of the shell 5 is provided with an opening (not shown in the figure) to facilitate the assembly of the side plates 2 and the end plates 3 into the shell 5. The cross-sectional area of ​​the opening 31 is larger than the cross-sectional area of ​​the explosion-proof valve so that the explosion-proof valve can properly vent.

[0030] Thus, the side plate 2 and end plate 3 are positioned between the electrode assembly 1 and the outer casing 5, providing stable support for the electrode assembly 1. The support portion also provides additional support to the bent portion of the electrode assembly 1, improving the structural strength of the bent portion, preventing the formation of weak areas and causing electrode cracking, and reducing the risk of broken electrode sheets being discharged to the outside through the explosion-proof valve and causing fire or explosion. The end plate 3 separates the end of the electrode assembly 1 from the explosion-proof valve, preventing the end of the electrode assembly 1 from blocking the explosion-proof valve in the event of battery thermal runaway. The opening 31 connects to the accommodating space 4, forming a venting channel, allowing a large amount of gas generated during thermal runaway to be discharged to the outside through the opening 31 and the explosion-proof valve, preventing the accumulation of internal pressure in the cell from causing an explosion, and improving the safety and stability of the lithium-ion battery.

[0031] Furthermore, the side plates 2 and end plates 3 made of mica material have sufficient hardness, are not easily deformed, and have good chemical and electrochemical stability, which can support the electrode assembly 1 and achieve an insulating connection between the electrode assembly 1 and the outer shell 5.

[0032] It is understandable that the materials of side plate 2 and end plate 3 can also be high-temperature resistant insulating materials such as ceramics, which will not be listed in detail here.

[0033] See Figure 1 In some embodiments, the surface curvature of the support portion facing the bend is equal to the curvature of the bend.

[0034] In this embodiment, the support part and the side plate 2 are integrally formed. The surfaces of the two support parts that are close to each other are arc surfaces, and the surfaces of the side plate 2 facing the outer shell 5 are flat surfaces, so as to fit with the inner wall of the outer shell 5. After the pole assembly 1 is assembled into the accommodating space 4, the bent part and the support part are spaced apart.

[0035] Thus, after the battery is assembled and charged, the electrode assembly 1 expands, and the bent part can fit tightly with the support part, so that the support part can stably support the bent part and improve the structural strength of the bent part, avoiding stress concentration and the formation of weak areas in the bent part; the side plate 2 abuts against the inner wall of the outer shell 5, so that the outer shell 5, the side plate 2 and the end plate 3 can jointly support the electrode assembly 1, improve the overall structural strength of the battery, and improve the safety and stability of the lithium-ion battery.

[0036] See Figure 2 In some embodiments, the opening 31 extends along the height direction of the pole group 1, and the cross-sectional area of ​​the opening 31 is smaller than the cross-sectional area of ​​the end of the pole group 1.

[0037] In this embodiment, the two ends of the opening 31 are arc-shaped, and the arc of the two ends of the opening 31 is smaller than the arc of the bend.

[0038] In this way, the space of the end plate 3 can be fully utilized to increase the area of ​​the opening 31, thereby increasing the exhaust volume. This allows a large amount of gas generated during thermal runaway to be discharged to the outside in a timely manner through the explosion-proof valve, preventing the accumulation of internal pressure in the battery and causing an explosion. The end plate 3 abuts against the end of the electrode assembly 1, which can limit the position of the electrode assembly 1 inside the accommodating space 4, preventing the electrode assembly 1 from shifting under gas impact, and improving the safety and stability of the lithium-ion battery.

[0039] It is understandable that the opening 31 can also be a rectangular opening, which can limit the position of the end of the electrode group 1 and separate the electrode group 1 from the explosion-proof valve. No further examples will be given here.

[0040] See Figure 3 In some embodiments, a first through hole 21 is provided on the side plate 2, and a second through hole 32 is provided on the end plate 3. Both the first through hole 21 and the second through hole 32 communicate with the accommodating space 4. Further, in some embodiments, multiple first through holes 21 are provided, and the multiple first through holes 21 are symmetrically arranged on both sides of the opening 31 along its length.

[0041] In this embodiment, multiple second through holes 32 are provided, and the multiple second through holes 32 are respectively provided on the surfaces of the side plate 2 and the bending part, and the multiple first through holes 21 and the multiple second through holes 32 are provided at intervals.

[0042] Thus, by opening the first through hole 21 and the second through hole 32, the weight of the side plate 2 and the end plate 3 can be reduced, and multiple exhaust channels can be formed when the battery experiences thermal runaway, so as to avoid excessive pressure accumulation inside the battery and cause an explosion. The symmetrical arrangement of the first through hole 21 can make the structural strength of both sides of the side plate 2 more balanced and achieve uniform exhaust.

[0043] It is understandable that the second through hole 32 can also be opened on the surface corresponding to the plane portion of the pole group 1. The setting position and number of the first through hole 21 and the second through hole 32 can be adjusted according to actual needs, and will not be listed in detail here.

[0044] See Figure 3 In some embodiments, the diameter of the first through hole 21 is in the range of 2mm-5mm, and the diameter of the second through hole 32 is in the range of 2mm-5mm.

[0045] In this embodiment, the diameter of the first through hole 21 is the same as the diameter of the second through hole 32. The diameter of the first through hole 21 can be any value between 2mm and 5mm or any range between two values, such as 2mm, 3mm, 4mm, 5mm, etc.

[0046] Thus, by limiting the apertures of the first through hole 21 and the second through hole 32, the exhaust efficiency can be improved while ensuring the structural strength of the side plate 2 and the end plate 3, preventing gas from accumulating inside the battery and improving the safety of the lithium-ion battery.

[0047] It is understandable that the diameter of the first through hole 21 and the diameter of the second through hole 32 may be different. The diameter of the first through hole 21 and the diameter of the second through hole 32 cannot be too large, as this will affect the structural strength of the side plate 2 and the end plate 3. Nor can they be too small, as this will affect the exhaust effect. The diameter of the first through hole 21 and the diameter of the second through hole 32 can be adjusted according to actual needs, and will not be listed in detail here.

[0048] See Figure 1 In some embodiments, the thickness of the outer shell 5 ranges from 0.3 mm to 1 mm.

[0049] In this embodiment, the outer shell 5 is made of aluminum material, and the cover plate is fixedly connected to the outer shell 5. The thickness of the outer shell 5 can be any value between 0.3mm and 1mm or any range between two values, such as 0.3mm, 0.5mm, 0.7mm, 0.9mm, 1mm, etc.

[0050] In this way, the outer casing 5, side plate 2, and end plate 3 can jointly provide support for the electrode assembly 1, improving the overall structural strength of the battery. Furthermore, the outer casing 5 can restrict the position of the side plate 2, end plate 3, and electrode assembly 1, preventing them from being impacted by gas and shifting after thermal runaway. This ensures that the explosion-proof valve can communicate with the containment space 4 and release gas to the outside in a timely manner, thereby improving the safety of the lithium-ion battery.

[0051] It is understandable that the outer shell 5 can also be made of metal materials such as steel. The material and thickness of the outer shell 5 can be adjusted according to actual needs, which will not be listed in detail here.

[0052] See Figure 1 and Figure 3 In some embodiments, the length of the side plate 2 is L1, the length of the outer shell 5 is L2, and L2-L1≥5mm is satisfied. The side plate 2 is symmetrically arranged inside the outer shell 5, that is, the distance between the two ends of the side plate 2 and the corresponding two ends of the outer shell 5 is the same.

[0053] In this embodiment, the length of the pole group 1 is equal to the length L1 of the side plate 2, and the difference between the length L2 of the outer shell 5 and the length L1 of the side plate 2 can be 5mm, 6mm, 7mm, 8mm, 9mm, etc.

[0054] Thus, the end of the outer shell 5 protrudes from the end of the side plate 2, which provides space for the assembly of the cover plate and the outer shell 5, making it easier to fix the cover plate to the end of the outer shell 5 by welding, reducing assembly interference and improving the stability of the lithium-ion battery.

[0055] It is understandable that the difference between the length L2 of the outer shell 5 and the length L1 of the side plate 2 cannot be too small, otherwise it will cause assembly interference between the cover plate and the side plate 2.

[0056] See Figure 3 In some embodiments, the length of the end plate 3 is L3, the minimum length of the opening 31 is L4, and L3-L4≤20mm is satisfied.

[0057] In this embodiment, the center of the opening 31 coincides with the center of the end plate 3, and the portions of the end plate 3 without openings 31 are symmetrically arranged. That is, the maximum width of one side of the portion of the end plate 3 without openings 31 is less than or equal to 10mm.

[0058] Thus, the end plate 3 abuts against the end of the electrode assembly 1, providing stable support for the end of the electrode assembly 1 and allowing the explosion-proof valve to communicate with the accommodating space 4 through the opening 31. When the battery experiences thermal runaway, a large amount of gas is promptly discharged to the outside, preventing pressure buildup and lithium-ion battery explosion, thereby improving the safety of the lithium-ion battery.

[0059] It is understandable that the difference between the length L3 of the end plate 3 and the minimum length L4 of the opening 31 should not be too large. If it is too large, it will cause the area of ​​the opening 31 to become smaller, affecting the exhaust volume, or the size of the end plate 3 to be too large. The length L3 of the end plate 3 and the minimum length L4 of the opening 31 can be adjusted according to the size of the pole group 1 and the explosion-proof valve, which will not be elaborated here.

[0060] See Figure 1 In some embodiments, the gap between the bent portion and the support portion is less than 1 mm.

[0061] In this way, space can be reserved for the expansion of electrode assembly 1, avoiding the electrode assembly 1 from being too tightly attached to the side wall 2 and end plate 3 after expansion, which would affect the assembly effect. This allows the support part of electrode assembly 1 to abut against the bending part after expansion, improving the structural strength of the bending part, avoiding the formation of weak areas and preventing breakage after being impacted by gas, and improving the stability of lithium-ion battery.

[0062] Understandably, the gap between the bending part and the support part cannot be too large. If it is too large, it will cause the pole group 1 to sway within the side plate 2 and the end plate 3, which is not conducive to restricting the position of the pole group 1.

[0063] It should be noted that when the lithium-ion battery is fully charged, the electrode assembly 1 expands due to lithium-ion intercalation. After expansion, the bent portion of the electrode assembly 1 fits against the arc-shaped surfaces of the two supporting portions, allowing the supporting portions to provide stable support for the bent portion, improving the structural strength of the bent portion, ensuring uniform stress on the electrode assembly 1, and increasing the mechanical strength of the electrode assembly 1. When the lithium-ion battery experiences thermal runaway, the side plate 2 and end plate 3 can protect and support the electrode assembly 1, reducing the risk of tearing and breakage of the bent portion of the electrode assembly 1, thereby reducing the number of electrode fragments ejected with the gas from the explosion-proof valve. At the same time, the end plate 3 can isolate the electrode assembly 1 from the explosion-proof valve, preventing the electrode assembly 1 from blocking the explosion-proof valve when gas generation is intense, thus reducing the risk of fire and explosion.

[0064] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A lithium-ion battery, characterized in that, include: A pole group (1) is provided with a bending portion; Side plate (2) and end plate (3), the side plate (2) and the end plate (3) together form an accommodating space (4) for accommodating the pole group (1), and the inner wall of the side plate (2) is provided with a support part corresponding to the position of the bent part; The outer casing (5) is provided inside the electrode assembly (1), the side plate (2) and the end plate (3); The cover plate is connected to the outer shell (5). An explosion-proof valve is provided on the cover plate. The end plate (3) is located at the end of the side plate (2) facing the explosion-proof valve. The end plate (3) has an opening (31) corresponding to the position of the explosion-proof valve. The opening (31) is connected to the accommodating space (4).

2. The lithium-ion battery according to claim 1, characterized in that, The surface curvature of the support portion facing the bending portion is equal to the curvature of the bending portion.

3. The lithium-ion battery according to claim 1, characterized in that, The opening (31) extends along the height direction of the pole group (1), and the cross-sectional area of ​​the opening (31) is smaller than the cross-sectional area of ​​the end of the pole group (1).

4. The lithium-ion battery according to claim 1, characterized in that, The side plate (2) has a first through hole (21) and the end plate (3) has a second through hole (32). Both the first through hole (21) and the second through hole (32) are connected to the accommodating space (4).

5. The lithium-ion battery according to claim 4, characterized in that, The diameter of the first through hole (21) is in the range of 2mm-5mm; and / or the diameter of the second through hole (32) is in the range of 2mm-5mm.

6. The lithium-ion battery according to claim 4, characterized in that, Multiple first through holes (21) are provided, and multiple first through holes (21) are provided on both sides of the opening (31) along its length.

7. The lithium-ion battery according to any one of claims 1-6, characterized in that, The thickness of the outer shell (5) ranges from 0.3 mm to 1 mm.

8. The lithium-ion battery according to any one of claims 1-6, characterized in that, The length of the side plate (2) is L1, and the length of the outer shell (5) is L2, and L2-L1≥5mm.

9. The lithium-ion battery according to any one of claims 1-6, characterized in that, The length of the end plate (3) is L3, the minimum length of the opening (31) is L4, and L3-L4≤20mm is satisfied.

10. The lithium-ion battery according to any one of claims 1-6, characterized in that, The gap between the bent portion and the supporting portion is less than 1 mm.

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